When fly strike occurs on horses despite prevention, immediate wound management is critical to prevent escalation of a painful welfare emergency.
Active fly strike causes intense pain from maggot-produced proteolytic enzymes dissolving living tissue. Each hour that strike goes untreated allows additional tissue penetration and damage. The welfare imperative is immediate, comprehensive treatment with adequate sedation and analgesia. Inadequate treatment — removing only visible maggots without cleaning deeply enough — leaves larvae to continue causing damage. The emotional difficulty of seeing a severely struck wound should not prevent the thorough cleaning necessary for effective treatment, which, despite causing short-term discomfort, is far better welfare than continued maggot activity.